Physical modeling of tsunamis generated by three‐dimensional deformable granular landslides

Abstract

Tsunamis generated by deformable granular landslides are physically modeled in a three‐dimensional tsunami wave basin based on the generalized Froude similarity. The dynamic landslide impact characteristics were controlled by means of a novel pneumatic landslide generator. The wave amplitudes, periods, and wavelengths are related to the landslide parameters at impact with the landslide Froude number being a dominant parameter. Between 1 and 15% of the landslide kinetic energy at impact is converted into the wave train energy. The wave amplitudes decay in radial and angular directions from the landslide axis. The first wave crest mostly travels with speeds close to the theoretical approximation of the solitary wave speed. The measured tsunami wave profiles were either of the nonlinear oscillatory or nonlinear transition type depending primarily on the landslide Froude number and relative slide thickness at impact. The generated waves range from shallow to deep water depth regimes, with the majority being in the intermediate water depth regime. Wave characteristics are compared with other two‐ and three‐dimensional landslide tsunami studies and the results are discussed.